The present invention relates generally to a variety of improvements of a liquid jet pump and, more particularly, to a pump suitable for jetting a liquid exhibiting a high viscosity.
There is a push-down head type of pump as a liquid jetting pump. For example, as illustrated in FIG. 7, a well-known pump includes a mounting cap 102 fitted to an outer periphery of a neck portion 101 of a container 100 and a cylinder 104 fixed to an interior of the container through the cap and having a suction valve 103 provided in an inner lower edge part extending downward within the container. The pump also includes a stem 106 having an annular piston 105 fitted to the interior of the cylinder and protruding from a lower part of the outer periphery thereof while being so provided as to be vertically movable in an upward biased state within the cylinder. The pump further includes a head 108 with a nozzle 107, this head being provided in continuation from an upper edge of the stem 28 and a coil spring 111 for always biasing upward a vertically movable member 110 constructed of a discharge valve 109 provided in an inner upper part of the stem, the stem and the push-down head. A liquid within the container is sucked into the cylinder 104 through the suction valve 103 by moving the vertically movable member up and down, and the intra cylinder liquid is jetted out of the tip of the nozzle 107 through the discharge valve 109 from the stem.
Further, an engagement member 112 fixedly fitted to an upper part of the cylinder is helically attached to an outer surface of the upper part of the vertically movable member in a state where the vertically movable member is pushed down. On this occasion, the lower edge part within the stem is liquid-tightly sealed by a cylindrical member 13 fixed to the lower edge of the cylinder.
Moreover, the cylinder lower edge part is reducible in diameter, and a plurality of ribs 114 are provided in a peripheral direction on the inner surface of the diameter-reducible portion. The coil spring 111 is attached by securing it slower edge to the upper surface of each of the ribs 114 through a flange of the cylindrical member 113 and fitting its outer surface to the inner surface of the diameter-reducible portion.
In this type of conventional pump, when the vertically movable member is raised after jetting the liquid by pushing down the vertically movable member, as illustrated in FIG. 7, the liquid to be sucked into the cylinder is sucked zig-zag. If a viscosity of the liquid to be reserved is high, a suction quantity per unit time is small (conspicuous with a viscosity as high as over 4000 cps), and, as a result, there is such an inconvenience that it takes much time from the vertically movable member to return to a maximum ascent position.
It is a first object of the present invention, which was contrived to obviate the defects inherent in the above prior art, to provide an excellent liquid jetting pump enabling the vertically movable member to quickly return to the ascent position even when containing the high-viscosity liquid and easy to manufacture at a low cost by modifying a slight part of structure of this type of conventional pump.
In addition to the above object, the present invention aims at solving the technical problems that the liquid jetting pump is desired to obviate as will hereinafter be described.
According to the conventional pump, there are disadvantages in which the liquid remaining in the nozzle after jetting the liquid drops out of the tip thereof, and the liquid remaining at the tip edge part within the nozzle is to be dry-solidified. This dry-solidification is neither desirable in appearance nor preferable because of hindering the jetting operation of the liquid as the case may be.
It is a second object of the present invention to provide an excellent liquid jetting pump capable of eliminating the liquid leakage and, besides, preventing the dry-solidification of the liquid as much as possible as well as providing an improvement of the prior art pump described above.
Further, there is provided a pump exhibiting such an advantage that the pump can be easily manufactured at the low cost because of being manufactured by modifying a slight part of the structure of the prior art pump.
A pump type liquid discharge container has the following defect. If the liquid contained has a relatively high viscosity, the liquid remaining within a nozzle hole after finishing the discharge of the liquid may drop out of the tip of the nozzle hole, and this liquid dropping may spoil a reliability of a consumer on the discharge container.
For eliminating the above defects, as disclosed in Japanese Utility Model Laid-Open Number 1-17976, the present applicant has applied a liquid discharge container constructed such that the bar-like portion is erected from an inner lower part of the cylinder, the upper part of the bar-like portion is inserted into the stem constituting a part of the operating member, the bar-like portion is inserted long into the stem when pushing down the operating member, the stem is negative-pressurized while removing the bar-like portion from within the stem when the operating member rises, and the liquid within the nozzle of the push-down head fitted to the upper edge of the stem can be thus sucked back.
In the above liquid discharge container, when the operating member is raised, the bar-like portion erecting from within the lower part of the cylinder is removed from within the stem, and the intra nozzle liquid is sucked back by the negative-pressuring the interior of the stem due to the removable thereof. Hence, if the operating member is insufficiently pushed down, a length of insertion of the bar-like portion inserted into the stem is also short. Accordingly, there is also insufficient negative-pressurization in the interior of the stem due to the removable of the bar-like portion when the operating member is raised, and there exists a defect in which the intra nozzle liquid is insufficiently sucked back due to the insufficient negative-pressurization.
It is another object of the present invention to obviate such a defect.
According to a first characteristic point of the present invention, for accomplishing the above objects, a liquid jetting pump comprising a mounting cap 2 fitted to a container neck portion, a cylinder 3 fixed to a container through the cap 2 and including a suction valve 9 provided in a lower edge part extending downward within the container, a stem 28 having an annular piston 27 fitted to the interior of the cylinder 3 and protruding from a lower part of the outer periphery thereof while being so provided as to be vertically movable, a push down head 30, with a nozzle 29, so provided in continuation from an upper edge of the stem 28 as to be vertically movable above the mounting cap 2, a discharge valve 31 provided in an upper part within the stem 28 and a coil spring 38 for always biasing upward a vertically movable member 4 constructed of the stem and the push-down head. A liquid within the container is sucked into the cylinder 3 through the suction valve 9, and a liquid within the cylinder 3 is jetted out of the nozzle 29 via the discharge valve 31 from the stem by moving the vertically movable member 4 up and down, there is provided an improvement characterized in that a plurality of ribs 10 for securing the lower edge of the coil spring 38 are arranged at a lower edge part within the cylinder 3 in a protruded state in a peripheral direction, and liquid passageways 50 passing both on an inner side and on an outer side of the lower edge of the coil spring 38 are provided between the plurality of ribs.
Herein, if an engagement recessed portion 11 for receiving and securing the lower edge of the coil spring is provided on the upper surface of the rib. The engagement of the spring and securing the passageway are facilitated.
Further, the vertically movable member 4 is so constructed as to be possible of engaging by push-down, the engagement recessed portion 11 is formed as an engagement recessed portion 11 with its inside surface and upper surface opened, a flange 21 fixedly fitted to the lower edge part of each of the engagement recessed portions 11 is protruded from an outer periphery of a lower edge of a topped peripheral wall 20 and a window hole 23 communicating with an interior and an exterior of the peripheral wall 20, and there may be provided a cylindrical member 19 constructed so that an outer periphery of an upper edge of the peripheral wall 20 can be liquid-tightly fitted to an inner surface of the stem lower edge in a push-down engaged state.
Furthermore, an auxiliary spring 26 may be interposed between the cylindrical member 19 and a valve member 18 of the suction valve 9, and the suction valve member 18 is thereby always biased in a valve closing direction.
For example, the head 30 is raised from a state shown in FIG. 1 by detaching the helically fitted portion of the vertically movable member, and, when pushing down the thus raised head 30, the interior of the cylinder 3 is pressurized, with the result that the liquid in the cylinder passes inside through the stem 28 enough to open the discharge valve 31 and is jetted outside out of the nozzle 29 from the portion of the vertical cylinder 32 of the head. Subsequently when stopping the push-down of the head 30, the vertically movable member 4 is raised by a resilient force of the coil spring 38, and the interior of the cylinder 3 is negative-pressurized, whereby the discharge valve member 35 descends relatively to the vertically movable member 4, and the valve hole is closed. When the discharge valve 31 closes, the suction valve is opened by the negative pressure within the cylinder 3, and the intra container liquid is led into the cylinder 3 via the suction valve 9. Thereafter, the suction valve is closed by a biasing force of the auxiliary spring 26 as well as a self-weight of the suction valve member 18.
The thus led liquid flows across on both sides internally externally of the coil spring 38 and rises, with the result that the vertically movable member 4 is raised quickly.
According to a second characteristic of the present invention, a liquid jetting pump constructed to suck a liquid within a container mounted therein by pushing down a push-down head 226 and jet the liquid out of a nozzle 225 protruding forwardly of the head 226, wherein the nozzle 225 is so formed as to ascend forward obliquely, and there is provided a discharge valve 241 housing a ball-like valve member 243 for closing a valve seat 242 provided at a proximal edge part within the nozzle 25, the valve member 243 being movable back and forth within the nozzle 225.
Herein, in a liquid jetting pump comprising, a mounting cap 202 fitted to a container neck portion, a cylinder 203 fixed to a container through the cap 202 and including a suction valve 209 provided in a lower edge part extending downward within the container, a stem 222 provided so that said stem 222 is vertically movable in a central portion within the cylinder in an upward biased state, an annular piston 223 having its outer peripheral surface slidably fitted to the inner surface of the cylinder 203 and connected to a lower part of the outer surface of the stem 222 to permit a flow of liquid in the inner peripheral surface lower part, an annular auxiliary piston 224 so fitted to the lower part of the outer periphery of the stem as to be vertically movable at a predetermined stroke, having its outer peripheral surface slidably attached to the inner surface of the annular piston and formed so that a through-hole 229 holed in a peripheral wall portion of the stem is openable and closable, a head 226, with a nozzle 225, so provided in continuation from an upper edge of the stem as to be vertically movable above the mounting cap, and a discharge valve 241 incorporating a ball-like valve member 242 to make the valve member 243 movable back and forth within the nozzle, a valve member 243 serving to close valve seat 242 provided at a proximal edge part within the nozzle 225 protruding forwardly of the head 226, wherein the liquid within the cylinder is led into the stem via the opened through-hole 229 and jetted out of the nozzle 225 through a discharge valve 241 by pushing down the push-down head, and the liquid within the container is sucked into the cylinder through a suction valve 209 by negative-pressurizing the interior of the cylinder when the push-down head 226 is raised, wherein the through-hole 229 can be closed by the auxiliary piston 224 only in a maximum ascent position of the stem.
Further, the auxiliary piston 224 may be possible of engaging with the cylinder 203 in the closed state of the through-hole 229 in the maximum ascent position of the stem 222 but possible of disengaging after the through-hole 229 has been opened by pushing down the head 226.
When the head 226 is raised by detaching the helically fitted portion of the vertically movable member 204, the upper surface of the auxiliary piston 224 is finally engaged with a downward stepped portion 233 of an inner cylinder 215a, and an engagement protrusion 232 of the auxiliary piston 224 runs over and engages with an engagement protrusion of the inner cylinder. Then, only the stem rises till the lower surface of the auxiliary piston 224 closely contacts an upward stepped portion 230 of the stem. On this occasion, the auxiliary piston 224 descends relatively to the stem, and the stem stops in a state where the through-hole 229 is closed.
When the pushing down the head 226 from this state, the auxiliary piston 224 is raised by the liquid pressure relatively to the stem 222, whereby the through-hole 229 is opened. However, the auxiliary piston 224 stops in a maximum ascent position due to the mutual engagements of the respective engagement protrusions 232, 234. Then, the through-hole 229 certainly opens. Subsequently, the respective engagement protrusions are disengaged for the first time after the downward stepped portion 231 of the stem has engaged with the upper surface of the auxiliary piston, and the auxiliary piston 224 descends together with the stem 222. Further, on this occasion, the liquid in the cylinder 203 flows via the opened through-hole 229 and is jetted outside via the nozzle 225 from the stem 222 by opening the discharge valve 241. On the other hand, the discharge member 243 is extruded up to the tip part of the engagement protrusion 244 by the liquid pressure.
Subsequently, when releasing the head 226 from being pushed down, the vertically movable member 224 is raised by the resilient force of the coil spring 220, and the discharge valve member 243 moves toward the valve seat 242 by the negative-pressurization within the cylinder 203 and then opens. Till this discharge valve 227 is closed, the liquid in the stem 222 flows back into the cylinder 203 via the through-hole 229, and correspondingly the intra nozzle liquid flows back into the stem. In the meantime, the suction valve 209 won""t open. When the discharge valve 241 is closed, the suction valve 209 opens, with the result that the intra container liquid is continuously led into the cylinder 203 till the vertically movable member 204 reaches the maximum ascent position.
In the maximum ascent position of the stem 222, the through-hole 229 reverts to a state where it is closed.
An embodiment relative to a second characteristic of the present invention will hereinafter be described with reference to the drawings.
FIGS. 8 to 11 illustrate one embodiment of the present invention, wherein the numeral 201 designates a liquid jet pump. The pump 201 includes a mounting cap 202, a cylinder 203 and a vertically movable member 204.
The mounting cap 202 serves to fix the cylinder 203 to a container 205 and is constructed such that an inward-flange-like top wall 208 extends from an upper edge of a peripheral wall 207 helically-fitted to an outer periphery of a container cap fitted neck portion 206.
The cylinder 203 is fixed to the container 205 through the mounting cap 202 and is provided with a suction valve 209 in a lower edge portion extending in the interior of the container.
In accordance with this embodiment, the cylinder 203 has a flange 211 protruding outward from the outer peripheral upper portion of a cylindrical peripheral wall 210, and a flange-like valve seat 213 descending inward obliquely is protruded from the window hole peripheral part opened at the center of the bottom wall 212. Further, a fitting cylindrical portion 214 is protruded downward from the peripheral edge of the lower surface of the bottom wall 212. An upper edge of a suction pipe is attached to this fitting cylindrical portion 214, and its lower part extends in the lower edge part in the container.
Further, an engagement member 215 for engaging the vertically movable member 204 in the push-down state is fixedly fitted to the upper edge part of the peripheral wall 210. The engagement member 215 is constructed such that the fitting cylindrical portion fitted via a rugged engagement element to the outer periphery of the upper edge of the cylinder 203 perpendicularly extends from a doughnut-like top plate, and an inner cylinder 215a fitted to the upper edge of the inner peripheral of the cylinder 203 extends perpendicularly from the inner peripheral edge of the top plate. The inner cylinder 215a and an upper edge inner surface of the cylinder 203 are prevented from being turned round by the engagement of vertical protrusions with each other, and a thread for helical fitting of the vertically movable member is formed along the inner periphery of the upper portion of the inner cylinder 215a. 
Then, the outward flange 211 is placed via a packing 216 on the upper surface of the container neck portion 206 and is caught by a top wall 208 of the mounting cap 202 helically fitted to the outer periphery of the neck portion and by the upper surface of the container neck portion 206.
The suction valve 209 is constructed so that the suction valve member for clogging the valve hole formed in the inner peripheral edge of the valve seat 213 is so provided on the valve seat 413 as to be vertically movable at a predetermined stroke with its lower surface closely contact therewith.
In accordance with this embodiment, the lower surface peripheral edge portion is so tapered as to be closely fitted to the upper surface of the valve seat 213, and there is provided the cylindrical suction valve member 217 with its lower edge surface opened. Further, the member 217 is constructed such that a plurality of rectangular plate-like engagement protrusions 218 are formed in the peripheral direction on the lower edge part of the outer periphery thereof, the lower edge surface of the coil spring 220 for biasing upward the vertically movable member 204 is secured to the upper surface of a plurality of rectangular plate ribs 219 formed in the peripheral direction on the inner, peripheral lower edge portion of the peripheral wall 410 of the cylinder 403, and the member 217 is vertically movable till each engagement protrusion 218 impinges on the lower surface of the coil spring 220. Note that a plurality of ribs generally designated by 221 in the Figure are formed in the peripheral direction on the outer peripheral upper portion of the suction valve member 217.
The vertically movable member 204 includes a stem 222, an annular piston 223, an auxiliary piston 224 and a push-down head 226 with a nozzle 225.
The stem 222 is provided so that the central portion within the cylinder 203 is vertically movable in an upward biased state, and, in accordance with this embodiment, the lower edge surface takes a cylindrical shape with the lower edge surface closed and includes a flange 227 protruding outward from the lower part of the outer periphery.
The annular piston 223 is so provided as to be movable integrally with the stem by attaching its outer peripheral surface to the inner surface of the cylinder 203 liquid-tightly and slidably while being integrally linked to the lower portion of the outer surface of the stem 222 so that the liquid is allowed to flow along the lower portion of the inner peripheral surface.
In accordance with this embodiment, an upward skirt-like upper slide portion 223b and a downward skirt-like lower slide portion 223c are protruded from the upper and lower portions of the outer peripheral portion of a cylindrical proximal member 223a. The respective slide portions are so press-fitted to the inner peripheral surface of the cylinder liquid-tightly and slidably. Further, a plurality of connecting rods 230 erecting upward outwardly obliquely from the outer peripheral edge of the upper surface of the flange 227 of the above stem 222 are provided in the peripheral direction, and tips thereof are integrally connected to the lower portion of the inner surface of the proximal portion 223a of each annular piston 223.
The auxiliary piston 224 is so fitted to the outer peripheral lower portion of the stem 222 as to be movable up and down at a predetermined stroke while making its outer peripheral edge slidably contact the inner surface of the annular piston 223 and has a through-hole 229 so holed as to be openable and closable in the stem peripheral wall.
In accordance with this embodiment, an upward skirt-like inside slide portion 224b protruding from the inner peripheral upper edge of a cylindrical proximal portion 224a is liquid-tightly slidably to the outer peripheral surface of the stem 222, and a downward skirt-like outside slide portion 224c protruding from the outer peripheral lower portion of the proximal portion 224a is liquid-tightly slidably fitted to the inner peripheral surface of a proximal portion 223a of the annular piston 223. Further, a cylindrical valve piece 224d extends downward from the inner peripheral lower portion of the proximal portion 224a, and an engagement cylindrical portion 224e protrudes from the upper part of the outer periphery of the proximal portion.
On the other hand, an upward stepped portion 230 is formed in a predetermined position along the lower portion of the outer periphery of the stem 222, while a downward stepped portion 231 is formed in a predetermined position along the upper portion of the stepped portion 230, thereby making it the vertically movable from a state where the lower surface of the cylindrical valve piece 224d is closely fitted to the upper surface of the upward stepped portion 230 to a state where it impinges on the lower surface of the downward stepped portion 231.
Further, a through-hole 229 is formed in the lower portion of the peripheral wall of the stem between the upward stepped portion 230 and the downward stepped portion 231.
Then, when the vertically movable member 204 is pushed down from an ascent position, the auxiliary piston 224 is relatively raised by the liquid pressure (by an air pressure when using a pump with no liquid in the cylinder for the first time) with respect to the stem 222, with the result that the through-hole 229 opens. On the other hand, when the vertically movable member 204 rises, the lower edge of the inner cylinder 215a contacts and engages with the upper surface of the engagement cylindrical portion 224e of the auxiliary piston 224, and, when the stem 222 further rises, the lower surface of the cylindrical valve piece 224e closely contacts the upward stepped portion 232, with the result that the through-hole 229 is closed.
Further, in accordance with this embodiment, in the closed state of the through-hole 229 in the stem maximum ascent position, the auxiliary piston 224 is so constructed as to be possible of engaging with the cylinder 203 but possible of disengaging after opening the through-hole 229 by pushing down the head 226.
In accordance with this embodiment, the engagement protrusion 232 is formed along the upper edge part of the outer periphery of the engagement cylindrical portion 224e. On the other hand, the downward stepped portion 233 is formed in the predetermined position along the lower edge part of the inner periphery of the inner cylinder 215a of the engagement member 215, and the engagement protrusion 234 engaging with the above engagement protrusion 232 is formed downwardly of the stepped portion 233. When the stem 222 is raised, the upper surface of the engagement cylindrical portion 224e contacts and engages with the lower surface of the above stepped portion 233, and the respective engagement protrusions 232, 234 are engaged with each other. When the stem 222 is further raised, the lower edge of the cylindrical valve piece 224d impinges on the upper surface of the upward stepped portion 230, thereby closing the through-hole 229. Further, when the head is push down from this state, the auxiliary piston 224 initially certainly engages with the inner cylinder 215a due to the mutual engagement of the engagement protrusions. Accordingly, the through-hole 229 is surely opened, and subsequently the upper surface of the inside slide portion 224b is engaged with the downward stepped portion 231 of the stem 222, thereby disengaging the respective engagement protrusions. Then, the auxiliary piston 224 descends together with the stem 222.
Further, on this occasion, the auxiliary piston 224 plays the role of shutting off the outside air introducing through-hole 235 formed in the cylinder 203. If the through-hole 235 is formed in the upper portion of the peripheral wall of the cylinder, and when the vertically movable member 204 rises, the outside air flows from between the stem 222 and the inner cylinder 215a and is led into the container negative-pressurized via this through-hole 235. If the stem 222 is in the maximum ascent position, the upper edge of the engagement cylindrical portion 224e of the auxiliary piston 224 air-tightly contacts the lower edge of the inner cylinder 215a, thereby shutting off the exterior and interior of the container.
The push-down head 226 is provided in continuation from the upper edge of the stem 222 so that the upper portion of the mounting cap 202 is movable up and down. In accordance with this embodiment, the push-down head 226 includes a cylindrical casing 236 having its peripheral wall extending perpendicularly from the top wall peripheral edge and its lower edge surface opened. The lower edge of a vertical cylinder 237 perpendicularly extending from the lower surface central portion of the top wall of the casing 236 is attached to the outer peripheral upper edge of the stem 222, thus fixing it to the stem 422. Further, a horizontal cylinder 238 with its proximal portion opened to the front surface of the upper portion of the vertical cylinder 237 penetrates the casing peripheral wall and thus protrudes forward, thus forming this horizontal cylinder 238, a bent cylindrical member 239 fixedly fitted to the tip of the horizontal cylinder and the nozzle 225. The nozzle 225 is constructed so that the whole part exclusive of the tip thereof ascends forward obliquely while its tip descends obliquely. With this construction, it is possible to prevent the liquid from dropping.
Moreover, a thread formed along the outer periphery of the vertical cylinder 237 with respect to the portion protruding downward from the casing 236 meshes with the thread of the engagement member 215 when pushing down the vertically movable member 204 and is thus made possible of engaging therewith in the state where the vertically movable member 204 is pushed down. On this occasion, the lower edge part of the outer periphery of the vertical cylinder 237 is light-tightly fitted to the inner periphery of a downward skirt-like annular protruded piece 240 provided on the inner surface of the inner cylinder 215a of the engagement member 215.
The nozzle 225 incorporates the discharge valve 241. The discharge valve 241 is constructed such that the ball-like valve member 243 for closing the valve seat 242 formed in the proximal portion within the nozzle 225 is so housed as to be movable back and forth.
In accordance with this embodiment, the inward-flange-like valve seat 242 is formed in the nozzle proximal portion, and, besides, a plurality of notched grooves are formed in the peripheral direction in the internal fitting portion of the horizontal cylinder 238 of the bent cylindrical member 239 constituting the tip part of the nozzle 225. Then, the engagement protrusion 244 capable of engaging wit the valve member 243 to permit the flow of liquid is protruded in the peripheral direction at the tip part of the inner surface of the nozzle.
Further, in accordance with this embodiment, a plurality of spring pieces 245 are protruded integrally from the lower surface of the stem, and the thread of the vertically movable member 204 engages with the thread of the inner cylinder 215a. Then, when the vertically movable 204 engages with the cylinder in the pushed-down state, each spring piece 245 is press-fitted to the upper surface of the top wall of the suction valve member 217. With this construction, the suction valve can be surely closed during a transportation while certainly pushing down the suction valve member 217.
The respective members are properly selectively composed of synthetic resins, metals and materials such as particularly elastomer exhibiting an elasticity.
Note that the pump according to the preset invention is not limited to the embodiment discussed above, and a variety of specific structures of the pump can be selected on condition that the pump is of the push-down head type.
As discussed above, the pump of the present invention is constructed so that the nozzle ascends forward obliquely, and there is provided the discharge valve in which the ball-like valve member for closing the valve seat formed at the proximal portion within the nozzle is so housed in the nozzle as to be movable back and forth. Hence, it hardly happens that the valve member extruded forwardly of the nozzle by the liquid pressure immediately reverts to the valve seat closed state by the self-weight but moves to and from substantially along the flow of liquid. Accordingly, if there is set a large distance enough to make the back-and-forth movements from the valve seat, a backflow quantity also increases, and it is possible to prevent the liquid leakage and the liquid dry-solidification preferably.
Further, the pump exhibits such advantages that the pump can be constructed by modifying a slight part of structure of the conventional pump and is therefore easily manufactured at a low cost.
Moreover, the pump according to the present invention includes the annular piston having its outer peripheral surface slidably attached to the inner surface of the cylinder and its inner peripheral surface lower part so connected to the lower part of the outer surface of the stem as to permit the flow of liquid. The pump also includes the auxiliary piston with its outer peripheral surface slidably attached to the inner surface of the annular piston and with the through-hole formed in an openable/closable manner in the peripheral wall portion of the stem. The pump further includes the discharge valve in which the ball-like valve member for closing the valve seat formed at the proximal edge part within the nozzle is so housed in the nozzle as to be movable back and forth. The intra cylinder liquid is led into the stem via the through-hole opened by pushing down the push-down head and jetted out of the nozzle through the discharge valve. When the head is raised, the liquid within the container is sucked into the cylinder through the suction valve by negative-pressurizing the interior of, the cylinder. Further, the through-hole can be closed by the auxiliary piston only in the stem maximum ascent position. Hence, when the head rises after jetting the liquid by pushing down the push-down head, the liquid within the stem flows back into the cylinder via the though-hole till the discharge valve is closed, and correspondingly the intra nozzle liquid flows back into the stem. Therefore, it is feasible to obviate the liquid dropping from the nozzle tip and prevent the liquid dry-solidification as much as possible.
Further, there are provided the annular piston sliding on the inner periphery of the cylinder and the auxiliary piston for opening and closing the through-hole. Therefore, the annular piston serving to guide the vertical movements of the stem can be formed solid and thick, the stable vertical movements of the stem can be made, and the durability is also enhanced.
Moreover, even if the container is carelessly turned over when used, since the auxiliary piston closes the through-hole in the stem maximum ascent position, the liquid leakage from the nozzle tip can be prevented as much as possible.
Further, the auxiliary piston 224 is possible of engaging with the cylinder 203 in the closed state of the through-hole 229 in the maximum ascent position of the stem 222 but possible of disengaging after the through-hole 229 is opened by pushing down the head 226. The thus constructed liquid jetting pump is capable of surely obviating such inconvenience that if the air still exists in the cylinder after being mounted in the container for the first time, the auxiliary piston is not raised by the air pressure relatively to the stem when pushing down the head.
According to the present invention, in a liquid jetting pump comprising: a mounting cap 302 fitted to a container neck portion; a cylinder 303 fixed to a container through the cap and including a suction valve 309 provided in a lower edge part extending downward into the container; a stem 323 having an annular piston 322 fitted to an interior of the cylinder 303, protruding from a lower part of an outer periphery and so provided as to be vertically movable in an upward-biased state; a push-down head 325, with a nozzle 324, disposed in continuation from an upper edge of the stem 323 and so provided as to be vertically movable above the mounting cap 302; and a discharge valve 326 provided with a valve member 331, for closing a valve hole formed in an inner upper part of the stem 323, so provided as to be vertically movable by a liquid pressure, wherein a liquid within the container is sucked into the cylinder 303 through the suction valve 309, and a liquid within the cylinder 303 is jetted out of the nozzle 324 through the discharge valve 326 from the stem by vertically moving a vertically movable member 304 constructed of the stem 323 and the push-down head 325, wherein a vertical stroke of the discharge valve member 331 is regulated so that Vbxe2x88x92Vc is equal to or larger than Va, where Va is the volumetric capacity of the nozzle 324, Vb is the volumetric capacity of the liquid passageway where the discharge valve member 331 is vertically movable, and Vc is the volume of the discharge valve member 331.
Further, herein, the suction valve 309 may be a suction valve 309 including a valve member 317 always biased in a valve hole closing direction by a resilient member 316.
Moreover, the suction valve 309 may be a suction valve 309 constructed of a dome-like valve plate 337, formed with a slit 336, for closing an opening of the lower edge of the cylinder 303 by fixedly fitting a lower edge periphery to an inner lower edge part of the cylinder 303.
Furthermore, the suction valve 309 may be a suction valve 309 constructed of a hollow truncated cone proximal portion 339, with its lower edge surface opened, for closing an opening of the lower edge of the cylinder 303 by fixedly fitting a lower edge periphery thereof to an inner lower edge part of the cylinder 303, and an elastic cylinder 341 so closely attached to an outer periphery of the wall of the proximal portion so as to be incapable of coming off and to liquid-tightly close a window hole 340 holed in the peripheral wall of the proximal portion 339.
It is used while mounted in the container 305 containing the liquid exhibiting the viscosity. For example, the head 325 is raised by detaching the helical fitted portion of the vertical movable member 304 from the state of FIG. 12, and, when pushing down the raised head 325, the interior of the cylinder 303 is pressurized. The liquid within the cylinder 303 then passes inside through the stem 323 enough to open the discharge valve 326 and is then jetted outside out of the nozzle 324 from the portion of the vertical cylinder 328 of the head. On this occasion, the discharge valve 331 is thrust up to the lower surface of the engagement bar 333 by the liquid pressure. Subsequently, when releasing the head 325 from being depressed, the vertically movable member 304 rises by the resilient force of the coil spring 330, and the interior of the cylinder 303 is negative-pressurized, with the result that the discharge valve 331 is lowered relatively to the vertically movable member 304 enough to close the valve hole. In the meantime, the liquid within the vertical cylinder 328 flows back into the cylinder 303, and correspondingly the liquid in the nozzle 324 flows back into the vertical cylinder 328. When the discharge valve 326 is closed, the suction valve 309 opens by the negative pressure within the cylinder 303. Then, after the liquid within the container has been led into the cylinder 303 through the suction valve 309, the suction valve is closed.
According to the present invention, in a liquid jetting pump comprising: a mounting cap 402 fitted to a container neck portion; a cylinder 403 fixed to a container through the cap 402 and including a suction valve 409 provided in a lower edge part extending downward within the container; a stem 422 provided so that said stem is vertically movable in a central portion within the cylinder in an upward biased state and having a discharge valve 427 in which a valve hole formed in an inner upper part is closed by a valve member 439 vertically movable by a liquid pressure; an annular piston 423 having its outer peripheral surface slidably fitted to the inner surface of the cylinder 403, and connected to a lower part of the outer surface of the stem 422 to permit a flow of liquid in the inner peripheral surface lower part; an annular auxiliary piston 424 so fitted to the lower part of the outer periphery of the stem as to be vertically movable at a predetermined stroke, having its outer peripheral surface slidably attached to the inner surface of the annular piston and formed with a through-hole 431 holed in a peripheral wall portion of the stem is openable/closable manner; and a head 426, with a nozzle 425, so provided in continuation from an upper edge of the stem as to be vertically movable above the mounting cap, wherein the liquid within the cylinder is led into the stem via the opened through-hole 431 and jetted out of the nozzle 425 through the discharge valve 427 by pushing down the push-down head, and the liquid within the container is sucked into the cylinder through a suction valve 409 by negative-pressurizing the interior of the cylinder when the push-down head 426 is raised, wherein the through-hole 431 can be closed by the auxiliary piston 424 only in a maximum ascent position of the stem.
Herein, a vertical stroke of the discharge valve member 439 may be regulated so that Vbxe2x88x92Vc is equal to or larger than Va, where Va is the volumetric capacity of the nozzle 455, Vb is the volumetric capacity of the liquid passageway where the discharge valve member 439 is vertically movable, and Vc is the volume of the discharge valve member 439.
Further, a suction valve member 417 constituting the suction valve 409 may be always biased in a valve hole closing direction.
Moreover, the auxiliary piston 424 may be always biased upward with respect the stem 422, and the through-hole 431 can be closed by the auxiliary piston 424 only when the stem 422 is raised at the maximum.
Furthermore, the auxiliary piston 424 may be possible of engaging with the cylinder 403 in a closed state of the through-hole 431 in the maximum ascent position of the stem 422 but possible of disengaging after the through-hole 431 by pushing down the head 426.
It is used while mounted in the container 405 containing the liquid exhibiting the viscosity. For example, the head 426 is raised by detaching the helical fitted portion of the vertical movable member 404 from the state of FIG. 20, finally the upper surface of the auxiliary piston 424 engages with the lower surface of the inner cylinder 415a with the result that the only the stem 422 rises and continues to rise till the lower surface of the auxiliary piston 424 closely contacts the upper surface of the upward stepped portion 432 of the stem. On this occasion, the auxiliary piston 424 is lowered relatively to the stem 422, and the stem 422 stops in the state where the through-hole 431 is closed.
When pushing down the head 426 from this state, the auxiliary piston 424 rises relatively to the stem 422 by the liquid pressure enough to open the through-hole 431, and the liquid within the cylinder 403 passes via the opened through-hole 431 enough to open the discharge valve and is jetted outside out of the nozzle 425. On this occasion, the discharge valve 439 is thrust up to the lower surface of the engagement plate 441 by the liquid pressure.
Subsequently, when releasing the head 426 from being depressed, the vertically movable member 404 rises by the resilient force of the coil spring 420, and the interior of the cylinder 303 is negative-pressurized, with the result that the discharge valve 439 is lowered relatively to the vertically movable member 404 enough to close the valve. The liquid within the stem 422 flows back into the cylinder 403 till the discharge valve 427 is closed, and correspondingly the liquid in the passageway where the discharge valve member 439 moves up down flows back into the stem 422 disposed upstream of the discharge valve, and further the liquid within the nozzle 425 flows back into the passageway. In the meantime, the suction valve 409 won""t open. When the discharge valve 427 is closed, the suction valve 409 opens, whereby the liquid in the container is continuously led into the cylinder 403 till the vertically movable member 404 reaches the maximum ascent position.
In the maximum ascent position of the stem 422, it reverts to a state where the through-hole 431 is closed.
The present invention provides an excellent liquid jetting pump capable of causing no liquid dropping and, besides, preventing the liquid dry-solidification. In a liquid jetting pump comprising: a mounting cap 502 fitted to a container neck portion; a cylinder. 503 fixed to a container through the cap and including a suction valve 510 provided in a lower edge part extending downward into the container; a stem 521 having an annular piston 520 fitted to an interior of the cylinder, protruding from a lower part of an outer periphery and so provided as to be vertically movable in an upward-biased state; a push-down head 523, with a nozzle 522, disposed in continuation from an upper edge of the stem and so provided as to be vertically movable above the mounting cap 502; and a discharge valve 524 provided with a valve member 530, for closing a valve hole by placing it on a valve seat 529 provided on an inner upper part of the stem, wherein a liquid within the container is sucked into the cylinder through the suction valve by vertically moving a vertically movable member 504 constructed of the stem and the push-down head, and a liquid within the cylinder is jetted out of the nozzle through the discharge valve from the stem, there is provided an improvement characterized in that a bar-like member 505 with its upper edge part protruding into the stem is provided, a tip of the bar-like member is in a lower position of the valve seat 529 of the discharge valve in the maximum ascent position of the vertically movable member 504, the tip of the bar-like member protrudes with a gap along the periphery upwardly of the valve seat 529 by pushing down the vertically movable member, and the liquid existing downstream of the discharge valve flows back upstream of the discharge valve via the gap when the vertically movable member 504 is raised.
Further, the suction valve may be a suction valve 510a including a valve member 519 always biased in a valve hole closing direction by a resilient member 539.
Moreover, the suction valve may be a suction valve 510b including a suction valve member 519b having a weight that is more than twice the weight of the discharge valve member 530.
For instance, when pushing down the head 523 from the state of FIG. 31, the interior of the cylinder 503 is pressurized, and the liquid within the cylinder 503 passes inside through the stem 521 enough to open the discharge valve 524 and is jetted outside out of the nozzle 522 from the portion of the vertical cylinder 526 of the head 523. On this occasion, the discharge valve member 530 is thrust up to the lower surface of the engagement bar 531 when pushed up by the liquid pressure within the cylinder 503 and/or by the tip of the bar-like member 505. Subsequently when releasing the head 523 from being depressed, the vertically movable member 504 rises by the resilient force of the coil spring 528, and the interior of the cylinder 503 is negative-pressurized, with the result that the discharge valve 530 is lowered relatively to the vertically movable member 504 enough to close the valve hole. However, the valve member 530 won""t close till the tip of the bar-like member 505 retracts under the valve seat 529. Accordingly, in the meantime, the liquid within the vertical cylinder 526 surely flows back into the cylinder 503, and correspondingly the liquid in the nozzle 522 flows back into the vertical cylinder 526.
When the discharge valve 524 is closed, the suction valve 510 opens by the negative pressure within the cylinder 503. Then, after the liquid within the container has been led into the cylinder 503 through the suction valve 510, the suction valve is closed.
The above-described pump still has, though quite excellent, a room for the improvement in order to obtain a more preferable effect of preventing the liquid dropping.
An excellent liquid jetting pump capable of venting the liquid dropping and the liquid dry-solidification preferably is to be proposed. For this purpose, according to the present invention, in a liquid jetting pump comprising: a mounting cap 602 fitted to a container neck portion; a cylinder 603 fixed to a container through the cap and having its lower edge part extending downward into the container; a bar-like suction valve member 605 having its lower surface closely fitted onto a valve seat 613 provided in an inner lower part of the cylinder to form a suction valve 617 and erecting upward so as to be vertically movable at a predetermined stroke; a stem 622 having an annular seal portion 627 with its inner peripheral edge liquid-tightly slidably fitted to the outer periphery of the member 605, protruding from a lower edge of the inner periphery and being vertically movable in an upward biased state; an annular piston 623 so fitted to a lower edge part of the outer periphery of the stem as to be vertically movably at a predetermined stroke, having its outer peripheral edge slidably attached to the inner surface of the cylinder and formed so that a through-hole 631 holed in the lower edge part of the stem as to be openable and closable; and a push-down head 625, with a nozzle 624, provided in continuation from an upper edge of the stem 622 so as to be vertically movable above the mounting cap 602, wherein a liquid within the cylinder 603 is led into the stem via the opened through-hole 631 by pushing down the push-down head, and a liquid in the container is sucked up into the cylinder by negative-pressurizing the interior of the cylinder, there is provided the liquid jetting pump comprising: a discharge valve 626 in which a valve hole formed in an inner upper part of the stem is closed by a valve member 637 vertically moved by a liquid pressure, the suction valve member 605 including a vertical groove 640 for a liquid backflow that is formed along its outer periphery.
Further, vertical stroke of the discharge valve member 637 may be regulated so that Vbxe2x88x92Vc is equal to or larger than Va, where Va is the volumetric capacity of the nozzle 624, Vb is the volumetric capacity of the liquid passageway where the discharge valve member 637 is vertically movable, and Vc is the volume of the discharge valve member 637. Moreover, a suction valve member 605 may be a suction valve member 605 always biased in a valve hole closing direction by a resilient member 641.
It is used while mounted in the container 606 containing the liquid exhibiting the viscosity. For example, the head 625 is raised by detaching the helical fitted portion of the vertical movable member 604 from the state of FIG. 35, and, when pushing down the raised head 625, the interior of the cylinder 603 is pressurized. The liquid within the cylinder 603 then thrusts up the annular piston 623, passes via the opened through-hole 631 enough to open the discharge valve 626 and is then jetted outside out of the nozzle 624. Further, the liquid within the cylinder 603 flows into the stem 622 through the vertical groove 640 of the suction valve member 605 also, on this occasion, the discharge valve 637 is thrust up to the lower surface of the engagement bar 639 by the liquid pressure.
Subsequently, when releasing the head 625 from being depressed, the vertically movable member 604 rises by the resilient force of the coil spring 620, and the annular piston 623 descends relatively to the stem 622 enough to close the through-hole 631. With the negative-pressurization in the cylinder 603, the discharge valve member 637 closes the valve hole, ad the discharge valve thereby closes. In the meantime, the liquid within the passageway where the discharge valve member 637 moves up an down flows back into the stem 622 disposed upstream of the valve seat 638, and correspondingly the liquid within the nozzle 624 flows back int the above passageway. Further, the liquid in the stem 622 passes along the vertical groove 640 of the suction valve member 605 and flows back into the cylinder 603. On the other hand, the suction valve 617 is opened by negative-pressurizing the interior of the cylinder 603, and the liquid within the container is led into the cylinder 603 through the suction valve 617. After the discharge valve 626 has been closed, the liquid within the container is continuously led into the cylinder 603 through the suction valve 617 till the vertically movable 604 reaches the maximum ascent position.
Provided is an excellent liquid jetting pump capable of preventing the liquid dropping and, besides, the liquid dry-solidification. According to the present invention, in a liquid jetting pump comprising: a mounting cap 702 fitted to a container neck portion; a cylinder 703 fixed to a container through the cap and including a suction valve 714 provided in a lower edge part extending downward into the container; a stem 717 having its lower edge surface closed and provided so that the stem is vertically movable in a central portion within the cylinder in an upward biased state and including a discharge valve 721 with a valve hole so holed in an upper part of the interior as to be closed by a valve member 722 vertically moved by a liquid pressure; an annular piston 718 so fitted to a lower edge part of the outer periphery of the stem as to be vertically movable at a predetermined stroke, having its outer peripheral surface slidably fitted to the inner surface of the cylinder and so provided as to be make openable closable a through-hole 728 holed in the lower-edge part of the stem; and a head 720, with a nozzle 719, so provided in continuation from an upper edge of the stem as to be vertically movable above the mounting cap, a liquid within the cylinder is led into the stem via the opened through-hole 728 and jetted out of the nozzle 719 through a discharge valve 721 by pushing down the push-down head, and the liquid within the container is sucked into the cylinder through a suction valve 714 by negative-pressurizing the interior of the cylinder when the push-down head 720 is raised, there is provided an improvement characterized in that the annular piston 718 is always biased upward with respect to the stem, and the through-hole 728 is so formed as to be closable only in a maximum ascent position of the stem.
Further, a vertical stroke of the discharge valve member 722 may be regulated so that Vbxe2x88x92Vc is equal to or larger than Va, where Va is the volumetric capacity of the nozzle 719, Vb is the volumetric capacity of the liquid passageway where the discharge valve member 722 is vertically movable, and Vc is the volume of the discharge valve member 722.
It is used while mounted in the container 705 containing the liquid exhibiting the viscosity. For example, the head 720 is raised by detaching the helical fitted portion of the vertical movable member 704 from the state of FIG. 42, and, when pushing down the raised head 720, the interior of the cylinder 703 is pressurized. The liquid within the cylinder 703 then passes via the opened through-hole 728, flows from the stem 717 enough to open the discharge valve 721 and is jetted outside out of the nozzle 719. Moreover, on this occasion, the discharge valve member 722 is through up to the lower surface of the engagement plate 736.
Subsequently, when releasing the head 720 from being depressed, the vertically movable member 704 rises by the resilient force of the coil spring 727, and the interior of the cylinder 703 is negative-pressurized, with the result that the discharge valve member 722 is lowered relatively to the vertically movable member 704 enough to close the valve hole, thereby closing the discharge valve 721. In the meantime, the liquid within the passageway where the discharge valve member 722 moves up and down flows back into the stem 717 disposed upstream of the valve seat, and correspondingly the liquid in the nozzle 719 flows back into the above passageway. Also, the liquid within the stem 717 passes via the through-hole 728 and flows back into the cylinder 703. On the other hand, the suction valve 714 is opened by negative-pressurizing the interior of the cylinder 703, and the intra container liquid is led into the cylinder 703 through the suction valve 714.
Even after the discharge valve 721 has been closed, the liquid in the container is continuously led into the cylinder 703 till the stem 717 reaches the maximum ascent position. In the maximum ascent position of the stem 717, the annular piston 718 engages with the lower surface of the inner cylinder 712a of the engagement member 712 and then descends relatively against the biasing force of the coil spring 730, and the through hole 728 is closed.
Provided is an excellent liquid jetting pump capable of eliminating the liquid dropping and, besides, preventing the liquid dry-solidification. According to the present invention, in a liquid jetting pump comprising: a mounting cap 802 fitted to a container neck portion; a cylinder 803 fixed to a container through the cap and including a suction valve 814 provided in a lower edge part extending downward into the container; a stem 820 provided so that the stem is vertically movable in a central portion within the cylinder in an upward biased state and including a discharge valve 824 with a valve hole so holed in an upper part of the interior as to be closed by a valve member 826 vertically moved by a liquid pressure, the stem 820 being provided with the discharge valve 824 closed by the valve member 826 vertically movable at a predetermined stroke in a lower part of the outer periphery of the stem; an annular piston 821 so fitted to a lower edge part of the outer periphery of the stem as to be vertically movable at a predetermined stroke, having its outer peripheral surface slidably fitted to the inner surface of the cylinder and so provided as to be make openable closable a through-hole 836 holed in the peripheral wall of the stem; and a head 823, with a nozzle 822, so provided in continuation from an upper edge of the stem as to be vertically movable above the mounting cap, wherein the liquid within the cylinder is led into the stem via the opened through-hole 836 and jetted out of the nozzle 822 through a discharge valve 824 by pushing down the push-down head, and a liquid within the container is sucked into the cylinder through a suction valve 814 by negative-pressurizing the interior of the cylinder when the push-down head 823 is raised, there is provided the liquid jetting pump comprising: a check valve 825, provided in the lower edge part of the stem, for permitting a one-way flow into the cylinder from within the stem.
Further, a vertical stroke of the discharge valve member 826 may be regulated so that Vbxe2x88x92Vc is equal to or larger than Va, where Va is the volumetric capacity of the nozzle 822, Vb is the volumetric capacity of the liquid passageway where the discharge valve member 826 is vertically movable, and Vc is the volume of the discharge valve member 826.
Furthermore, the non-return valve 825 may be a non-return valve 825 for integrally and vertically movably supporting a valve plate 832 closing the lower surface of the valve hole holed in a bottom wall of the stem by use of a plurality of bar-like elastic portions 833 protruding from an inner surface of a cylindrical proximal portion 831 fixedly fitted to the lower edge of the stem. The discharge valve 814 may be a discharge valve 814 for integrally and vertically movably supporting a valve plate 815 closing an upper surface of a valve hole holed in the lower edge part of the interior of the cylinder by use of a plurality of bar-like elastic portions 817 integrally protruding from the inner surface of a cylindrical proximal portion 816 fixedly fitted to the lower edge part of the interior of the cylinder. Then, a pressure required for opening the check valve 825 may be smaller than a pressure required for opening the suction valve 814.
Moreover, engagement protrusions 845, 846 for regulating a stroke of the vertical movement of each valve plate may be protruded in a predetermined position under the check valve plate 832 and in a predetermined position above the suction valve plate 815.
It is used while mounted in the container 805 containing the liquid exhibiting the viscosity. For example, when the head 823 is raised by detaching the helical fitted portion of the vertical movable member 804 from the state of FIG. 47, the annular piston 821 is lowered relatively to the stem 820 and ascends up to the maximum ascent position in the closed state of the through-hole 836. Further, in the maximum ascent position of the stem 820, the annular piston 821 engages with the lower surface of the inner cylinder 812a of the engagement member 812.
When pushing down the raised head 823 from this state, the annular piston 821 rises relatively to the stem 820, and the through-hole 836 is opened. Then, the interior of the cylinder 803 is pressurized, and the liquid passes via the opened through-hole in the cylinder 803 and is jetted outside out of the nozzle 822 through the opened discharge valve 824 from the stem 820. Moreover, on this occasion, the discharge valve 826 is thrust up to the lower surface of the engagement plate 814 by the liquid pressure.
Subsequently, when releasing the head 823 from being depressed, the vertically movable member 804 rises by the resilient force of the coil spring 830, and the through-hole 836 is again closed. Then, the check valve 825 is opened by negative-pressurizing the interior of the cylinder 803, and the liquid within the stem 820 flows back into the cylinder. Then, the discharge valve 826 is lowered relatively to the vertically movable member 804. Note that the liquid within the stem 820 flows back into the cylinder trough the check valve 825 till the discharge valve is closed, and correspondingly the liquid within the passageway where the discharge valve 826 moves up and down flows back into the stem 820 disposed upstream of the discharge valve. Further the liquid in the nozzle 822 flows back into the above passageway.
The discharge valve 826 reaches above the valve seat 843, and the discharge valve 824 is closed. Hereupon, the check valve 825 is also closed, and the liquid within the container is continuously led into the cylinder 803 after opening the suction valve 814 (there is a slight difference depending on the pressures necessary for opening the non-return valve 825 and the suction valve 814 and also a possibility in which the non-return valve 825 and the suction valve 824 open simultaneously) till the vertical movable member 804 reaches the maximum ascent position.
According to a third characteristic of the present invention, in a pump type liquid discharge container comprising: a mounting cylinder 902 attached to an outer surface of a container neck portion; a cylinder 903 having a suction valve 907 provided on an inner surface of a bottom portion and extending downward into the container from the mounting cylinder; a operating member 930, with a discharge valve, erected from within the cylinder by biasing it upward; and a push-down head 931, with a nozzle 934, provided at an upper edge of the operating member, a liquid in the container being sucked into said cylinder and a liquid in the cylinder being jetted out of the nozzle 934 by vertical movements of the operating member, wherein a suction valve 907 in a bottom portion within the cylinder is constructed of a self-closing valve with a valve hole 910 resiliently closed by a valve member 911, the operating member 930 is constructed of the push-down head 931, a stem 935 having a small-diameter cylinder 938 extending downward through an outward flange 937 from a lower edge of a cylindrical portion 936 extending downwards into the cylinder 903 while fixing its upper edge part to the push-down head, a lower member 940 provided with a large-diameter board portion 943 at a lower edge of a bar-like portion 942 extending downward while fixing its upper part into the cylindrical portion 936 and provided vertically with a passageway forming groove 941 in its outer surface and a cylindrical piston 950 including an inner cylindrical portion 951 fitted to the outer surface of the bar-like portion so as to vertically movable between the outward flange 937 of the stem and the board-like portion 943, the cylindrical piston is formed in a triple cylindrical shape connected through a flange, an outer cylindrical portion 953 is water-tightly fitted to a wall surface within the cylinder and an upper part of a middle cylindrical portion 952 is water-tightly fitted to an inner wall surface of the small-diameter cylinder 938, the interior of the upper part of the middle cylindrical portion communicates with the passageway forming groove 941, a discharge valve 944 is formed of the lower edge part of the middle cylindrical portion 952 and of the outer peripheral part of the board-like portion 943, and a friction resistance of the cylindrical piston 950 with respect to the inner wall surface of the cylinder 903 is set larger than a friction resistance with respect to the bar-like portion 942 and the small-diameter cylinder 938 as well.
In the state where the operating member 930 is raised, the cylindrical piston 950 is in the descending position with respect to the lower member 940, and, when pushing the push-down head 931 from a state where the discharge valve 944 is closed, at first the stem 935 and the lower member 940 are lowered with respect to the cylindrical piston 950 by which the outer cylindrical portion 953 is press-fitted to the inner wall surface of the cylinder 903. Then, with the descents thereof, the discharge vale 944 opens, and the lower edge of the small-diameter cylinder 938 of the stem 935 contacts the cylindrical piston 950, whereby the cylindrical piston 950 also descends. The liquid within the cylinder flows though inside the stem and is jetted out of the nozzle 934.
When releasing the push-down head 931 from the state where the operating member is lowered, at first the stem 935 and the lower member 940 are raised with pushing-up by the coil spring 935 while the cylindrical piston 950 remains stopped, and the discharge valve 944 is closed. Thereafter, the cylindrical piston 950 also rises, and, during this ascent, the suction valve 907 opens, with the result that the liquid is sucked into the cylinder.
By the way, as illustrated in FIG. 59, till the discharge valve 944 is closed with the ascent of the operating member from the lowered state of the operating member 930, the stem 935 and the lower member 940 rise with respect to the cylindrical piston 950 remaining stopped, and the upper part of the middle cylindrical portion 952 of the cylindrical piston 950 is press-fitted water-tightly to the inner wall surface of the small-diameter cylinder 938. Hence, it follows that there increases a capacity of the liquid outflow portion from the lower edge of the cylindrical piston 950 to the upper edge of the stem 935. The discharge 907 remains closed till the discharge valve 944 is closed, and, therefore, the liquid within the nozzle hole 933 is sucked back into the stem, corresponding to the quantity of the increased capacity.